Gold, from the earliest times to the present day, has been regarded as one of the most precious of metals. Next to osmium, iodium, and platinum, it is the heaviest of metals, being nineteen times heavier than water. Next to iron it is the most extensively diffused metal upon our planet. It occurs in granite, the oldest rock known to us, and in all the rocks derived from it. It is, however, much more common in alluvial grounds than among primitive and pyrogenous rocks. Nine-tenths of the gold which has been produced has been obtained from alluvial beds. Gold mines are generally situated at the extreme limits of civilization. Herodotus notes the fact and he is confirmed by Humbolt. It is first mentioned in Genesis ii: 11. It was found in the country of Havilah, where the rivers Euphrates and Tigris unite and discharge their waters into the Persian Gulf. Gold is never found in mass, in veins, or lodes; it is interspersed, in threads or flakes, throughout quartz or other rocks. It is the only metal of a yellow color; it is easily chrystallizable, and always assumes one or more of the symmetrical shapes,--such as the cube or octahedron. It affords a resplendent polish, and may be exposed, for any length of time, to the atmosphere without suffering change, and is remarkable for its beauty. Its malleability is such that a cubic inch will cover a surface of eighteen hundred square feet; and its ductility is such that a cube of four inches could be drawn into a wire which would extend around the earth. Gold in its relative value to silver has varied greatly at different periods.